FWIW, Water-Wetter is also a very effective corrosion inhibitor, and will prevent Galvanic Corrosion from occurring even in cooling systems running nothing but Distilled Water and one bottle WW (and which consist of aluminum, brass, copper, and other components all in the same loop).
I tested this a while ago, by taking two pieces of C110 99.998% pure copper (each about 1.5oz), two pieces of high-purity aluminum (each about 1.8oz), 5gal of Distilled H2O, two 2.5L "Beakers", and one bottle of Water Wetter.
In each of the beakers, I put one of the copper pieces and one of the aluminum. They were each filled with the Distilled Water, except one had been pre-mixed with Water Wetter to a 95:5 ratio (95% H2O).
I let them set over the course of 113 days, and would "agitate" the beakers (which were hermetically sealed immediately after being filled to reduce the influx of any ions that weren't copper or aluminum) whenever I thought to, or as often as 13x in one day and as little as 1x over the course of 4 days (out of town).
At Day 114, the just-H2O copper had become corroded beyond any hope of repair, it was just demolished.
The copper with the water wetter in it? NOTHING! Not even Varnish!
Now, even in my Computer's Custom Liquid-Cooling Loop, I use Water Wetter ANY TIME there is even a POSSIBILITY of mixed metals, no matter how close they are on the Galvanic Index (i.e. in my PC, it's 100% copper and brass, but still...)
I tested this a while ago, by taking two pieces of C110 99.998% pure copper (each about 1.5oz), two pieces of high-purity aluminum (each about 1.8oz), 5gal of Distilled H2O, two 2.5L "Beakers", and one bottle of Water Wetter.
In each of the beakers, I put one of the copper pieces and one of the aluminum. They were each filled with the Distilled Water, except one had been pre-mixed with Water Wetter to a 95:5 ratio (95% H2O).
I let them set over the course of 113 days, and would "agitate" the beakers (which were hermetically sealed immediately after being filled to reduce the influx of any ions that weren't copper or aluminum) whenever I thought to, or as often as 13x in one day and as little as 1x over the course of 4 days (out of town).
At Day 114, the just-H2O copper had become corroded beyond any hope of repair, it was just demolished.
The copper with the water wetter in it? NOTHING! Not even Varnish!
Now, even in my Computer's Custom Liquid-Cooling Loop, I use Water Wetter ANY TIME there is even a POSSIBILITY of mixed metals, no matter how close they are on the Galvanic Index (i.e. in my PC, it's 100% copper and brass, but still...)
